docker: new build interface script

The new build script can pass arguments directly to ubuntu.sh when
building, this is good for when you want a special build for example
when you don't need RTPS or Simulation

```
./Tools/docker_build.sh --no-sim-tools
```

In the future it can be extended if needed to generate multiple docker
images based on the same Dockerfile, if for example we only want to
build arm targets

Tools/docker_build.sh

@@ -0,0 +1,20 @@
+#!/bin/bash
+
+if [[ -z "${DOCKER_TAG}" ]]; then
+  TAG_NAME="latest"
+else
+  TAG_NAME="${DOCKER_TAG}"
+fi
+
+PX4_DOCKER_REPO="px4io/px4-dev:$TAG_NAME"
+BUILD_ARGS="${@}"
+PWD=$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )
+SRC_DIR=$PWD/../
+
+echo "[docker_build.sh]: Building [$PX4_DOCKER_REPO]"
+echo "[docker_build.sh]:  - with args: [$BUILD_ARGS]"
+
+docker build \
+  -t ${PX4_DOCKER_REPO} \
+  -f Tools/setup/Dockerfile "${SRC_DIR}" \
+  --build-arg INSTALL_ARGS="${BUILD_ARGS}"

Tools/setup/Dockerfile

@@ -27,13 +27,17 @@ COPY Tools/setup/ubuntu.sh /tmp/ubuntu.sh
 # We support pre-downloading the gcc arm none eabi compiler
 # to speed up build times, if the file is not present when
 # building, the ubuntu.sh script will download it from source
-COPY *gcc-arm-none-eabi-9-2020-q2-update-linux.tar.bz2 /tmp/gcc-arm-none-eabi-9-2020-q2-update-linux.tar.bz2
+COPY gcc-arm-none-eabi-9-2020-q2-update-linux.tar.* /tmp/
 # The PATH env is set within ubuntu.sh, but given how we
 # are running the image using `gosu` to avoid read-only problems
 # with the filesystem the env variable does not persist
 ENV PATH="/opt/gcc-arm-none-eabi-9-2020-q2-update/bin:$PATH"
 ENV PATH="/opt/jdk-14.0.2+12/bin:$PATH"
-RUN bash /tmp/ubuntu.sh --from-docker --with-java --with-rtps --no-sim-tools
+
+# For a complete list of INSTALL_ARGS options run:
+# ./Tools/setup/ubuntu.sh --help
+ARG INSTALL_ARGS
+RUN bash /tmp/ubuntu.sh --from-docker $INSTALL_ARGS
 
 ENV DISPLAY :99